Skin cancer is a significant public health concern which represents 50% of diagnosed cases of cancer in the United States. Ultraviolet radiation (UV) can cause molecular and cellular level damage, and is considered the leading environmental factor responsible for skin cancer. The prolonged exposure to UV radiation, such as from the sun, can lead to the formation of light dermatoses and erythemas, as well as increase the risk of skin cancers, such as melanoma, and accelerate skin aging processes, such as loss of skin elasticity and wrinkling.
The damaging effects of UV exposure can be suppressed by topical application of sunscreens which contain compounds that absorb, reflect or scatter UV, typically in the UVA (wavelengths from about 320 to 400 nm) or UVB (wavelengths from around 290 to 320 nm) range of the spectrum. Numerous sunscreen compounds are commercially available with varying ability to shield the body from ultraviolet light.
Zinc oxide is a particulate material that is useful as sunscreen, since it absorbs and scatters ultraviolet radiation. However, the inventors have recognized that a need exists for zinc oxide having enhanced optical properties, particularly for use in sunscreens and personal care products, and more particularly for enhanced UVA absorption.